Compound metal body and process of producing same.



EATENTED JULY 21,1908.

J. E. MON NOT. OOMEOUND METAL BODY AND EEOOESS OE EEOOOOING SAME.

I nl 51:4

APPLICATION FILED APR. 13,1907.

l UNITED sTArns PATENT OFFICE.

JOHN F. MONN OT, OF NEW YORK, `N Y., ASSIGNOR TO DUPLEX METALS COMPANY, OF NEW 'YORK Nl Y., A CORPORATION OF NEW YORK.

COMPOUND METALBODY PROCESS Oli PRODUCIN G SAME.

Specicaton of Letters Patent.

Patented July 21, 1908.

Original application led September 6, 1906, Serial No. 333,570. Divided and this application filed April 13, 1907.

Serial N0. 367,985.

To all whom 'it l:mty concern: I

Be it known that I, JOHN F. MoNNoT, a

- citizen of the United States, residing at New 'novel product, and consists in a method of uniting layers or strata of unlike metals, i. e., metals or alloys of unlike chemical nature, whereby such metals and alloys are united as firmly and permanently as Weld-united layers of iron or steel, for example; also in the product produced. The unondbetween A metals which are unlike in the above sense,

' subsequent behavior of the united bodies of produced according to the method herein described, is in all respects equivalent to the most perfect weld possible, insofar as` the metal is concerned; for which reason,and because the term weld is the one which would most naturally be applied-to such a union, by those skilled in the art, I term such union hereinafter a weld, without intending thereby to limit or confine myself to any particular theory as to the actual nature of the unionbetween the unlike metals.

.By the method herein described it is possible to produce compound metal ingots, and also 'manufactured articles of compound metal, such as plates, sheets, rods, tubes, wire and the like.

It is Well known that it is very difficult to unite, ermanently, unlike metals; and particularly to unite a ferrousmetal, such as wrought ironand the various steels, or metals like nickel and cobalt, with metals of a nonferrous nature, such as copper, silver, gold, aluminum, etc. I have found, and it is a lmatter of common knowledge and experience,

that ironand copper, 1ron-and silver, iron and aluminum, and similar pairs of unlike metals, cannot be weld-united or equivalently united by casting the copper, silver, aluminum, etc. at ,the ordinary casting temperatures of such metals, against the surface. of an iron or steel object to be coated.

The fundamental discovery upon which my new process rests is, that while unlike metals of high fusing temperature, such as those named above, do not weld readily or at all under ordinary conditions f metal working, nor by casting one of the metals at ordinary casting temperature against an unlikeI metal likewise of high, castingl temperature;y yet if the metal soA cast be cated, before casting, far above its melting point and ordinary casting temperature, and be cast at such abnormally high temperature, the lack of affinity between the metals observed at lower temperatures disappears, and the unlike metals contacted at such high temperature unite readily to form a union of an autogenous, permanent character equivalent to a true weld. Metals such as copper, s1lver and aluminum, at such a high temperature,

are in a condition which for the sake` of a name may be called a lsupermolten condition and display extraordinary chemical and physical activity, readily uniting With gases and other bodies, and also with wholly unlike metals,A such as iron and the various grades of steel; and I believe thatithe' same is' 80 tion of the phenomenon. Possibly it is due to disassociation of proximate molecules of the metals which stil melting point. It is commonly believed by physicists that persist at and near the ultimate molecules of .most substances in the solid state are associatedto form larger complex molecules-an association whlch persists to some extent after fusion, but steadily diminishes with increase of heat; and that the influence of heat upon chemical reactivity is due to this phenomenon. This peculiar increase of chemical reactivity o f certain molten metals and concomitant heightenmg of their affinities for certain other metals, Whether these aflinities be molecular, atomic thereof' durin `or the other.

to the uniting of unlike metals of the classes herein contemplated; the sole attempt of experimenters in the field of uniting unlike metals by casting one such metalagainst' the other having been'to heat the metal to be cast to a vpoint where it will remain liquid long enough to fill the mold completely, and, sometimes, to heat to or nearly to its melting point the metal against which the molten metal is cast. I am not, however, aware that any attempt has ever been made to produce temporarily between the contacting surfaces of the metals to be joined at the instant of casting the extremely high temperature utilized in the hereinafter described method.

Copper and steel may be taken as a pair of y unlike metals affording a typical example. Copper, at its ordinary casting temperature, dis lays practically no affinity for the totally un ike metal, steel, hardly wetting it and forming nounion with it which will withstand tools or heat changes, even if it be cast at such ordinary casting temperature a ainst the surface of the steel and held there (Iuring solidification. The best union that'can be formed in this manner, so far as known, is a mere adhesion or sticking together of the two metals, and not a true cohesion. The metals so united will se arate subse uently during working or by t e action of eat or shock, or can be separated readily by means of a tool. In a way, it may be said that the two metals behave as if their surfaces were merely fitted together and not really united. But if copper at the so-called supermolten temperature above referred to be contacted with the steel and `held against the surface solidification, the temperature of the mo ten metal being allowed to fall as soon as true wettin is effected, a union is formed which is'abso utely permanent and as strong as a true weld, the metals so joined being inseparable by change of temperature or by shock; and a coldnchisel or like tool, applied along the line of juncture of the two metals, will not follow said line readily as it would if. the metals were merely stuck together, but tends to dig into the one metal Nor will reheating the joined metals to a red heat and quenching in water result in separation of the metals. The union thus produced is equivalent to what, in the case of-united bodies of steel and iron, is called a weld; As tothe nature of the union thus produced, uncertainty exists; but it is known that when the process is pro pfrly carried out changes in the joined meta s,

any, film between the proximate surfaces,` the main portions of the bodies of joined metals possessing their ordinary properties. It may e that the union between the metals is a mere result of thorough wetting of the steel by the copper; a molecular contact and coherence between adjacent molecules of are confined to an excessively thiny copper and steel similar to that which unites the molecules of cop er and the molecules of steel each among t emselves or, again, it may be that the uniting layer is of a different composition from the joined metals and is an alloy of such metals, chemically or physically combined, a mixture, or solution. The existence of such an alloy' film seems-probable, because in the carrying outl of the roces's certain evidences ofslight solution o the iron in the copper, such yas might naturally accompany an served; but whether or not an alloyfilm is alloymg inter-action, have been obformed, and without restricting myself to the theory that any true alloy is formed, it is convenient to term the uniting layer between the joined metals, for the sake of a name, an

alloy film,

sense hereinafter.

Whatever the nature of the alloy film or uniting film, it is capable of indefinite exand I use said term in this tension since an ingot of two metalsv joined thereby may be extended to any desired ex-- tent, even to the thinnest sheets or wire, without the union failino, without the separation of the two metaIs, and without the development of liaws, pores or seams therein or therebetween, and even with substantial maintenance of the original relative proportions of the two metals; all. of which shows that the original union between the two metals still persists inthe coextended ware produced by Working the ingot, even down to thin sheets and wire.

In the case of copper, the supermolten temperature appears to be from 2500 to The super- 2800 Fahrenheit or higher. molten temperature'of s1lver is about .the same; that of aluminum is somewhat lower.

yThe temperatures named have not been determined with absolute accuracy, it being well known that it is difficult, if not impossible, to measure temperatures in the neighborhood of or exceeding 2000o F. with even approximate certaintyl and accuracy butv I have endeavored to determine these temperatures with the-best plyrometers readily obtainable, and believe t e figures given to be substantially correct. In practice, it is not necessary -to know accurately the temperature of thesupermolten metalgas it is easy to test the molten metal from time to time, as

it is being heated up, by dipping therein a test1 iece of the metal to be coated,.withdrawing 1t under circumstances precluding oxidation, and allowing the adhering film of molten metal, if any, to cool.. When the molten metal forms on the article so di which, when cold7 possesses t e qualities o the alloy film or welding film above recited,

it is known that the su ermolten temperature has been reached; Ih desirable to heat the metal somewhat hotter still, in order that there may be a margin of temperature available. In practice, the

ped a coatin ut even then it is workmen engaged in carrying out the process of which this is a division,.upon which Patent N0. 853,716, dated May 14, 1907, has issued and is described therein. As an illustration of the rocess claimed herein, I will describe the uniting of silver to steel. The difliculty,

or even impossibility, of uniting steel and silver by a joint equivalent toa weld between two pieces of steel, by methods heretofore known, is well recognized. And I will su pose that it is a steel ingot which isto e coated with silver, and thatall surfaces of the ingot are to be coated with a substantial thickness of silver, and then thecoated in ot l extended by rolling, hammering, orI the li ie,

to Aform sheets, rods, or other extended ware. The surface of the steel ingot is first brou ht to an absolutely clean metallic surface y Sandblasting or lother suitable mechanical method of removin scale, oxid, and the like, and then customarilgyispickled. In ickling I preferably use hydrochloric or ydrofluo'ric acid, as these acids form on the lsteel surface a non-oxygenated closely adhering protectivecoating of chlorid or fluorid,

which volatilizes readily at a later stage in the operation, exposing an absolutely clean and fresh metallic surface to the supermolten metal.

In pickling the steel may form an anode of an electric couple, when desired.

.-After pickling, it is best to heat the ingot preliminarily before contacting the same with the supermolten metal, to avoid abstraction of undue amounts of heat from thesupermolten metal. One method of conducting this preliminary heating Will be described hereafter, but others may be used. Customarily, I do not heat the ingot preliminarily above a red or low yellow heat.'

The heated ingot is then transferred to and immersed in Ka bath of supermolten silver, being rotected from oxidation as hereinafter descri ed, during the' transfer. onds contact of the supermolten metal with the heated ingot usuall suffices for the silver to unite with the stee -the exact time depending somewhat upon how hot the `steel was' heated preliminarily; experience soon teaches the workmen how .long the contact of the steel with the supermolten metal should continue. The surface of the steel ingot probably at once assumes. the temperature of the supermoltencopper., -Wl1en the entire coating is'to be formed from the metal of the supermolten bath, I then segregate from the main bodyof the supermolten metal alayer thereof, in contact with the surface of the ingot, ofsufiicient thickness to form the dethe 'solidifying metal and the base or core.

A few secsired coating, according to the method' described in my Patent 851,684, dated `April 30th, 1907, and withdraw the ingot and-se e.l gated layer of molten metal and cause the atter to solidify on the surface of the ingot, under conditions affording pressure between A If the segregated or cast-on silver layer forms an annulus surrounding the core, the self-` compression of the silver due to its contraction during solidication and cooling is ordinarily suiiicient. And in an application for Letters Patent iiled May 23, 1905, Sr. No.

261,739, I have illustrated and described means for applying positive pressure from an external source during solidification and cooling. n y

In the accompanying drawings I illustrate, rather dia rammatically, apparatus such as may be used in carrying out my process.

In said'drawingsz-Figure 1 represents a sectional view of 'one form of a aratus for carryin out thesaid process. ig. 2 shows in deta` section the construction of bottom plate and lower portion of casing preferably employed. Fig. 3 shows a sectional view of another form of casing which may be employed.

i In Fig. 1, lis a preliminary heating chamber for the ingot or core, 2 a furnace for heating a Crucible 3, containing a body of supermolten coating metal 4. 5 designates a ower hoist, here shown as an electrical oist, mounted on a suitable track so that it` can be moved from lace to place; and from said hoist is suspen ed, by means of a porto-r bar 6, the ingot 7, which-is the object to be coated. Said ingot is shown surrounded by a casin 8 having an internal diameter slightly larger than the external diameter of the ingot, and to said casing is connected a pipe 9, a portion of which is flexible, said pipe provided with a three-way valve 10. This pipe and the valve 10 are provided for supplying to the casing, when desired, an atmosphere of indifferent or neutral gas, such as roducer gas. Casing 8 has a weighted ead 11 which'insures-that when the casing'is lowered into the molten metal it shall sink therein to the desired'depth. 12 115 designates a bottom plate for the casing arranged to be secured to the Cingot 7 itself, by means of a screw 13. Said bottom plate is provided with a raised rib or ring 14 matchinga corresponding groove 15, in the lower edge of the casing, and adapted to coact with said groove to make a tight joint. For raising and-lowering the casing 8 with respect to the ingot 7, as ecial hoist 16, suspended like porter bar 6 om hoist 5, is pro- 125 vided. It has, in the form shown, two winding drums 17 upon which are wound cables 18 connected to opposite sides of the casing, so that said casing may be raised and lowered truly vertically.

45 v p process in this, the `protective atmosphere molten metal, or for similar reason. To

further exclude air from the surface of the molten metal, yI cover so much of its surface as possible with a layer of charcoal, a ring 2() ofv refractory material which floats on the sui'face of'the molten metal serving to maini tain a clear space in the center for the passage of the ingot andlcasing. I v

To assist in forming a tight joint between .the bottom plate and casin I provide in the groove 15 at the bottom of the casing packing material 21.

' As an alternative to the' above described apparatus for carryin out my process, I may use that shown ingFig. 3, which is much the saine as that above described except that the casing 8 is provided with inlets 23 in its sides, said inlets arranged to be closed at will' by a sliding shield or valve 24.y In carrying out the process with `this apparatus the casing without the bottom late 12 thereon is laced over the heating c amber 1, said casing being at the time filled with a protective atmosphere as above described, and the porter bar is lowered down throu h the casing, secured to the ingot or core to e coated and raised up into said casing again with the said ingot or core. The casing with the core 7 within it, is then'moved to one side, the bottom plate 12 applied, and then the casing is moved over the crucible 3 containing super molten coating metal, andl is lowered into said supermolten metal; the valve or closure 24 being raised as the openings 23 come to the surface of the moltenl metal so vthat said casing fillsthrough said o ening's 23. The casing with ingot andmo ten metal within it is then raised and the molten metal allowed to cool as before. In carrying out the within the casing when the filling holes 23 vare open, protects the surface of the ingot and the molten metal which l enters the casing against oxidation; and in fact no air can'enter the casing., because the holes 23 are submerged in the molten metal almost instantly after the closure 24 is raised, and during the possible brief instant while said openings are open but not completely submerged the outrush of gas from the casing will prevent the entrance of air; A v

''To hasten the filling'ofthe casing with molten metal, and to prevent trapping of 'as in the molten metal as it solidifies, I re erably apply suction to the outlet 25 o valve 10, having first set saidvalve -so as to cut off theentrance of gas and to place outlet 25-in communication with the interior of the casing. This 1s done, however, only after lthe molten metal has commenced to flow in. And when necessary or expedient, I reduce the fiuid ressure upon the 'oint between the bottom p at'e and casing, w ile raising either the casing shown in Fig. `1 or the casing shown in Fig. 3, by applying suction to the outlet 25 of valve 10.

The coated ingot produced in either of the Ways above described is usually workedh as by rolling (either at once, or after submission to a soaking heating to bring all the parts to a uniform temperature), to condense the metal of the coating and to extend it to shapes desirable for future working, such` as bars, rods, and plates. In such extension the joined metals lextend together without rupture of'union between them and the final article usually contains the saine relative 't i app ication No. 333,570, of which this 'is a division. l

The core or base or ingot coated as de scribed in this specification need not be iron or steel, lbut for most purposes an iron or steel base or core will be preferred. Hence in certain ofthe following claims I specify steel as the metal of such core or base; and this term steel I employ enerically to des@ ignate all forms of iron, inc uding not merely ordinary carbon steel, both low-carbon or mildl and high-carbon or hard, but also wrought iron (the properties of which are nearly'identical with those of mild steel) and e ingot into the casing without dipping is specifically claimed in my said ics various compound steels, such as tungsten steel, titanium steel, vanadium steel,'chrome steel, nickel steel, manganese steel, cobalt steel; also substantially .pure iron-f1.. e., the chemical element Fe, substantially free from carbon and other metalloidsI or impurities l 'and modifying ingredients.

'while the heat of the molten metal is transferred outwardly by the cooling of the casing walls, and' no opportunity is aHoi'ded for detrimental action upon either the main body of the steel orthat of the molten metal..

Such changes as take place, .or may take place, in either metal, are only in the excessively thin joining layer between; and since, as already explained, I do not limit myself to .any theory of how the union between the high reactive condition afforded by the supermolten temperature, would of course be detrimental to both. By limiting to a few seconds the periodof contact of the metals while one of them is in the supermolten condition, I limit to extreme thinness the oining layer of alloyed, mixed, interpenetrating, or otherwise-united metals.

In an application filed June 19, 1908, Sr. No. 439,284, I have claimed compound or clad metal articles com rising a coatin of copper, silver, gold, a uminum, and like metals, alloyed with ferrous metals, Weld-y united to ferrous metals, and a process of making such articles.

What I claim is 1. The process of producing compound bodies of unlike metals welded together which consists in contacting a-surface of one' such metal with a su ermolten mass of an unlike metal' and confP 'tions affording pressure between such solidifying layer and the surface against which it is cast.

3. The process of roducing compound bodies of ferrous and) non-ferrous metals welded together which consists in contacting the surface of a ferrous-metal object with av molten mass of a metal of the other such` group having a melting point above 900 F., such second metal maintained at a temperature much above its melting temperature, confining a portion of such molten metal, of

.substantial thickness, in contact with such ferrous-metal surface, and causing it to solidify thereon.

'unlike metal and con ining a portion of the I metal from such supermolten mass, of sub-w 4. The process of ,producing compound bodies of unlike metals welded together which consists in contacting the surface of a `steel object with a supermolten mass of silver, and confining a body of molten silver of substantial thickness in contact with such surface and causing it to solidify thereon.

' 5. The process of producing compound bodies `of unlike metals welded togetherv which consists in contacting a surf-ace of a steel object with a-supermolten massy of silver and confining a portion of the metal from such supermolten mass, of substantial thickness, in contact with such surface and causing it to solidify thereon.

' v6. The process of 'producin compound bodies of unlike metals wel ed together which consists in contacting a surface of a steel object with a supermolten mass ofsilver, segregating from said mass a substantial layer thereof immediately adjacent to4 suchisur'face and withdrawingA such segregated layer and the steel object together and causing `said segregated layer to solidify agai t said object under conditions affording ressure between such solidifying object and the steel object.

7. The process of producin compound bodies of unlike metals .wel ed together which consists in contacting a surfaceof one such metal with a su ermolten mass of an ng a portion of the stantial thickness, in contact with such surface, limiting the action of the supermolten metal on the solid metal by withdrawing such confined layer and the object against which the same is from the heating influence of the supermolten metal and causing such layer of molten metal to solidify.

8. The process of roducing compound bodies of unlike metafs) l which consists in contacting a surface of a steel body with a supermolten mass of silver, limiting to infinitesimal thickness the uniting layer thereby formed by limiting to a brief period the time of contact between the'metals while one of them remains in the superinseparably united,

molten condition, and causing a layer of the silver to solidify on the steel surface.

9. As a new article of manufacture, a ferrous base having a welded-on oreless dense coating of silver united thereto y a union resisting temperature changes, cutting tools i 6 o y i 894,162

of ininitesdimal thiclmess, said silver coating base and silver coating having been extended i having the properties of metal set rorn a together. A

Huid state. i In testimony whereof I aX my signature,

12. As a new article of manufacture, an in the presence of two Witnesses.

vextended metal article compris' a ferrous ,metal base and a continuous pore ess, dense JOHN F' MONNOT' coating of silver Weld-united thereto, by a Witnesses:

union resisting temperature changes, cutting J. F. KINDER,

tools and mechanical stresses, said ferrous H. M. MARBLE. f 

